Earlier quoted context omitted.
If the NFT contained the content hash, your and the creators public keys, a signed timestamp, and the signature of those parts by the content creator, then the content could be stored elsewhere no? Obviously you'd want to keep a copy yourself, but at least you could then prove to others the file you have really is the one the creator sold, no? No expert at these crypto things, in either sense, am I missing something?
Say you add all that information to the transaction, to verify it in the future you still need to run the original file through the same hash function to prove they match. Its common for image files to be modified, many times even automatically by the hosting service. They might compress it, remove unnecessary metadata, or add metadata for themselves. Any of that would break the hash, so you'd need to make sure any h…
Which is trivial, just download the file. The place where you bought the NFT would ideally have some facility where they guarantee you can download the correct file, otherwise why buy from them?
> But wait, that hash isn't guaranteed to be unique so really anyone could make another NFT pointing to the same URL and file hash, now they also own it? And anyone could just download the file, so they own it to?
Preimage attacks are quite hard to accomplish from what I understand against modern, secure hashes. If the hash used is later broken and a preimage attack is possible then yeah you're screwed. That's a risk you take.
As for exclusive ownership, I forgot in my initial reply to add another aspect I thought about which was the license. That is, some well-defined licenses should be specified, similar to the Creative Commons stuff, and the NFS should specify one of them. Then you know if you get copyright or not etc.
Enforcement of the license would of course be similar to other digital assets, ie hard to do unless you're big, that's just the nature of digital things.
Now, just to be clear, please don't take this to mean I'm advocating NFTs. I just think the way they're currently used seems to make them completely worthless, while in theory it might be possible to make them not quite worthless.